Commodore 1940 - Self Test Circuit

5. Self Test Circuit
SIGNAL
CONNECTOR
PIN
IC402
PIN 0468
(VERTICAL BLANKING)
FBT
PIN
@--i
C536
(HORIZONTAL BLANKING)
+8V
0623
_ ...... --oR
_ ...... --oG
R623
'---.t---o B
_----~J--I*--__o 0623
0108 0106
I
R512
<FIG. 11 SELF TEST CIRCUIT>
Self-test pattern should be available when the contrast control is rotated its maximum. With the signal cable
disconnected, the display shows full white raster which should extends beyond the bezel at the top and bottom.
The brightness should
be uniform in the region extending from the screen center. With the brightness control
detent, the brightness of the raster should be geater than
10 Ft-L.
28